Desempenho funcional de usuários de próteses totais convencionais e de overdentures mandibulares retidas por 2 e 3 implantes: um estudo observacional paralelo de 3 grupos.

Abstract

Conventional full dentures wearers show a reduction of masticatory capacity of around 55% compared to mandibular overdentures wearers; however, it is still uncertain whether the increase in the number of implants for retention of mandibular overdentures can positively influence functional parameters that interfere in obtaining an efficient masticatory function. Studies indicate that retained mandibular overdentures by three implants promote superior functional performance when compared to retention by 2 implants. This parallel cross-sectional observational study compared differences in bite strength, swallowing threshold and masticatory performance between 3 treatment strategies for mandibular edentulism: conventional complete denture, mandibular overdentures retained by 2 and 3 implants. A total of 36 edentulous patients were allocated to 3 study groups to receive the following rehabilitation treatments: I) conventional full prosthesis; II) mandibular overdenture retained by 2 implants and III) mandibular overdenture retained by 3 implants. The implants (Facility, 2.9x10mm) were installed using single-stage surgery and conventional loading and the prosthetic retention system used was of the button type (Attachment Equator). After 3 months of using the prosthesis, the functional evaluation was performed by i) recording the bilateral bite force using the gnatodynamometer device, ii) and chewing function tests: masticatory performance and swallowing threshold using artificial test food (Optocal) , processed quantitatively by the fractionation method in sieves. The Mann-Whitney test was used to compare central trends for independent samples. Values of p ≤0.05 were considered statistically significant. Compared to of conventional complete denture wearers, mandibular overdentures retained by 2 implants wearers showed increased bilateral bite strength, dominance on the right side and significantly better masticatory performance. Women obtained improved chewing performance and improved bilateral bite strength. Mandibular overdentures retained by 3 implants wearers showed decreased swallowing threshold time and improved masticatory performance. Compared to the group of overdentures retained by 2 implants, the group of overdentures retained by 3 implants did not show significant differences in all parameters. Compared to conventional complete denture wearers, overdentures retained by 2 implants wearers show better chewing performance and bite strength, while the group of overdentures retained by 3 implants showed a reduction in chewing time only. The groups of overdentures retained by 2 and 3 implants showed no differences between them for all evaluated parameters.